Children across the United States are insufficiently physically active. In response, numerous physical activity (PA) interventions have been developed and tested, the majority within the school setting. Unfortunately, these have resulted in limited, if any impact on children's PA. We feel that this absence of effect stems from a lack o tailoring at the school level and a resulting lack in institutionalization. To address the latter isue, we feel that it is important to leverage existing resources and capitalize on existing policies. Th state of South Carolina has instituted the role of Physical Activity Coordinators to promote PA among students across and beyond the school day. School PA Coordinators have enormous potential to increase PA among students by identifying and implementing school-specific approaches that leverage community resources to increase PA across the school day. However, while these positions are mandated by state law, the individuals in these positions often lack the training and support to maximize their impact. We believe PA Coordinators can have substantial impact on student's PA level with proper training and provision of modest curricular resources. Therefore, this study would: 1) develop training and resources for PA Coordinators that would, 2) enable the PA Coordinators to develop and implement evidence based practices for the promotion of PA in elementary school children across the school day. Goal: To determine the acceptability, feasibility, and effectiveness of properly trained and equipped school PA Coordinators to promote PA in elementary schoolchildren. AIM 1: Develop and pilot-test a standardized training course and resource toolkit for PA Coordinators. AIM 2: Determine the acceptability/feasibility of the PA coordinator training and the subsequent implementation of evidence-based interventions in an elementary school setting. AIM 3: Determine the effectiveness of properly trained and equipped PA Coordinators to promote objectively measured PA in elementary school youth. Study design: In year one, we will develop a training curriculum and implementation model for PA Coordinators. In year two, we will randomize four schools to receive the PA Coordinator training (n=2) or continue standard practice (n=2). A comprehensive process and impact evaluation will be conducted to determine acceptability of the intervention, factors influencing implementation fidelity/dose, and the effectiveness of the PA Coordinators to increase physical activity measured via accelerometry in children.